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The Claim: Lack of Sleep Increases Weight

Looking to lose a little weight? Portion size and exercise are crucial. But don’t forget about a good night’s rest.

Scientists have known for years that skimping on sleep is associated with weight gain. A good example was a study published in 2005, which looked at 8,000 adults over several years as part of the National Health and Nutrition Examination Survey. Sleeping fewer than seven hours a night corresponded with a greater risk of weight gain and obesity, and the risk increased for every hour of lost sleep.

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Credit
Christoph Neimann

More recent studies have taken a much closer look.

One published this year in The American Journal of Clinical Nutrition took a small group of men and measured their food intake across two 48-hour periods, one in which they slept eight hours and another in which they slept only four. After the night of abbreviated sleep, the men consumed more than 500 extra calories (roughly 22 percent more) than they did after eight hours of sleep. A University of Chicago study last year had similar findings in both men and women: subjects took in significantly more calories from snacks and carbohydrates after five and a half hours of sleep than after eight and a half hours.